The connection strings to databases
In the container upgrade process we use connection strings to connect to the SQL databases that must be upgraded. These connection strings are listed in the Docker Compose configuration file – docker-compose.upgrade.yml and in the Kubernetes specification file – mssql-upgrade.yaml.
All the database names in the connection strings are resolved with the sitecore prefix by default, for example, sitecore.Core. If your databases use another prefix you can specify it in the corresponding environment variable or Kubernetes secret. If you use custom database names which do not follow the [prefix].[database name] convention, you must specify the correct database names in the Docker Compose or Kubernetes specification files.
If the Kubernetes specification file contains the connection string for a database, the upgrade script and Sitecore item update procedure will be executed for that database.
If you do not want to upgrade some databases, you must delete their connection strings from the specification file.
You must not delete the connection strings for the Sitecore.Core and Sitecore.Master databases – they cannot be skipped in the upgrade process.
The Kubernetes specification files for the upgrade container have connection strings for only two xDB Collection shards by default. If your solution contains more xDB Collection database shards, you must add a connection strings for them by using the same format that is used for the other shards.
If you add connection strings for shard databases, you must increment the shard number in the connection string name, for example, shard 3 should be Sitecore_ConnectionStrings_Xdb_Collection_Shard3.
The Sitecore upgrade container does not support MongoDB databases. If your xDB Collection database is stored in MongoDB you must remove the Sitecore_ConnectionStrings_Xdb_Collection_Shard* connection strings from the specification files for the upgrade container.